45. Tunable LEDs and variable spectrum: when they are really needed.

In indoor agriculture marketing, tunable LEDs are often presented as a universal solution: more channels, more control, more yield.
From a technical point of view, the reality is different. In many contexts tunable spectrum is superfluous, in others it is crucial. This article clarifies when it is really needed, when it is not, and what the most common mistakes are.

What are tunable LEDs (in practical terms)

A tunable LED system allows you to dynamically change the relative intensity of different spectral channels (blue, green, red, far-red, UV, etc.) over time.

It is not a matter of:

• simple adjustment of total intensity

• static "growth/flowering" presets.

But about active spectrum management throughout the crop cycle, even on a daily or single-layer basis.

Fixed vs. variable spectrum

Fixed spectrum LEDs (well designed)

• Spectrum optimized for one or a few crops

• Maximum energy efficiency

• Simple and stable architecture

• Ideal for standardized productions

Tunable LEDs

• Spectrum adaptable to:

  • phenological stages

  • different species

  • morphological or quality objectives

• Increased hardware and software complexity

• Require control, data and expertise

The key point is one: flexibility has value only if it is actually used.

When tunable LEDs are NOT needed

In many indoor installations, tunable LEDs represent technological overdesign.

They are not needed if:

1. You grow only one species with a stable cycle

2. Your goal is solely average yield

3. You do not collect structured growth data

4. You have no control models or algorithms

5. Energy cost is a critical variable

In these cases, a well-tuned fixed spectrum ensures more consistent results, lower power consumption and greater reliability.

When tunable LEDs are really needed

There are scenarios where variable spectrum becomes a strategic lever.

Multi-crop production

When crops with different light requirements coexist in the same plant, tunable LEDs enable:

• adaptations by layer

• intelligent trade-offs

• greater uniformity of results

Morphology control

The spectrum directly affects:

• internode length

• leaf thickness

• plant compactness

• leaf-to-stem ratio

Examples:

• increase in blue → more compact plants

• increase in red → accelerated growth

• targeted use of far-red → controlled elongation

Here the spectrum is not used to increase yield, but to shape the plant.

Nutritional and sensory quality

Many secondary metabolites respond to:

• controlled light stresses

• selective UV

• pre-harvest spectral variations

Typical applications:

• aromatics

• premium baby leaf

• nutraceutical productions

In these cases, the variable spectrum becomes a tool of quality, not volume.

Research, development and A/B testing

In R&D contexts, fixed spectrum is a limitation.
Tunable LEDs allow:

• controlled comparisons

• varietal analyses

• development of optimized Growth Plans

Without variable spectrum, data remain incomplete.

The most common mistake: more channels = better results

Many systems promise 6, 8 or more channels, but without:

• reliable sensors

• real-time feedback

• growth models

The result is often:

• crop instability

• energy waste

• non-replicable results

A variable spectrum without data is just expensive light.

Variable spectrum and artificial intelligence

The true value of tunable LEDs emerges only when they are integrated into a system:

• data-driven

• with continuous feedback

• capable of automatically adapting light curves

In this scenario, the spectrum is not set, but optimized over time.
The LED becomes an intelligent actuator, not just a hardware component.

Operational Summary

Tomato+

Tomato+ designed its LED systems based on a clear principle: variable spectrum has value only if it is truly controllable.
That is why we use LEDs with 6 independent channels, capable of covering the entire photosynthetically active spectrum and adapting to different growth stages.
Each channel is individually managed by software to create dynamic and replicable light curves.
The system is supported by liquid cooling, which maintains stable LED temperature and preserves efficiency and spectral consistency over time.
The result is light that is accurate, reliable, and designed to work together with data

Conclusion

Tunable LEDs are not a shortcut to better yields.
They are an advanced tool that works only in mature, designed, data-driven systems.

The correct choice depends on the goal:

• simplicity → fixed spectrum

• control → variable spectrum

• continuous learning → variable spectrum + AI

Technology should be chosen for consistency, not for fashion

Thank you for reading this article. Keep following us to discover new content on hydroponics, vertical farming, and smart agriculture.

Tomato+ Team